With the release of CRM 2016 (2015 Update 1 for CRM Online), comes a new form rendering engine (referred to as Turbo Forms in some circles) was built to provide better performance of form loads. The two main changes are focused around loading process of the form and the handling of the cache.
However, while the new rendering engine was built to help with performance you may actually notice the opposite taking place. In heavily customized environment, you might experience long stalls during form loads with messages reading “requesting data from CRM” and/or “loading business logic”.
If you are currently being plagued by these messages, it may be a good idea to turn the new rendering engine off. To do this, simply go to: Administration -> System Setting, scroll all the way down and you will see the “Use legacy form rendering” option. Turning it to “yes” will disable the new engine.
While this will help in the short term, it is advised to figure out what on your form is causing conflict with the new engine so that it can be fixed and the new engine can be turned back on for even better performance. Microsoft is also aware of the issue and is looking at it within the Update Roll-up 1 Time frame.